Dein Unbekannter Bruder plot
Hamburg 1935. The anti-fascist Arnold Clasen returns from the concentration camp and rejoins his resistance group. Since he is guarded, he lives quietly and avoids contact with his comrades. In the afternoon and evening he goes to work as a film operator in the Orion-Lichtspiele cinema. Sometimes he comes with Renate, whom he loves. She comes from a middle-class family, but shares his political views. The isolation gives him problems, so he looks for the friendship of his contact man Walter. He wants to trust someone, but the distrust is great. The danger of betrayal from the outside world comes from their own ranks. After frequent arrests are made in the group, Arnold suspects that Walter is a traitor.